Composition containing a dicyanostyryl group, for forming a resist underlayer film capable of being wet etched

ABSTRACT

A resist underlayer film that exhibits removability and preferably solubility only in wet etching reagent solutions, while exhibiting good resistance to resist developers that are resist solvents or aqueous alkali solutions. The composition for forming a resist underlayer film includes a dicyanostyryl group-bearing polymer (P) or dicyanostyryl group-bearing compound (C) and includes solvent, and does not contain a protonic acid curing catalyst and does not contain an alkylated aminoplast crosslinking agent derived from melamine, urea, benzoguanamine, or glycoluril.

TECHNICAL FIELD

The present invention relates to a resist underlayer film-formingcomposition, an uncured resist underlayer film obtained by removing asolvent from an applied film comprising the resist underlayerfilm-forming composition, and a method for producing a patternedsubstrate and a method for producing a semiconductor device, each usingthe resist underlayer film-forming composition.

BACKGROUND ART

A lithography process in the production of a semiconductor has beenwidely known in which a resist underlayer film is formed between asubstrate and a resist film formed on the substrate, forming a resistpattern having a desired form. After forming the resist pattern, removalof the resist underlayer film and processing of the substrate areconducted, and, in these steps, dry etching is mainly used. Further,after processing the substrate, in the step of removing the unnecessaryresist pattern and the resist underlayer film, dry etching is used, but,for the purpose of simplifying the steps for process and reducing adamage to the processed substrate, wet etching using a chemical liquidis often used.

Patent Literature 1 discloses an improved ARC composition comprising:

a. a dye-grafted hydroxy-functional oligomer reaction product of apreliminarily selected phenol- or carboxylic acid-functional dye and apoly(epoxide) resin having an epoxy functionality of more than 2.0 toless than 10, wherein the reaction product has light-absorptionproperties effective for ARC application of a ground layer;

b. an alkylated aminoplast crosslinking agent derived from melamine,urea, benzoguanamine, or glycoluril;

c. a protonic acid curing catalyst; and

d. a solvent system comprising a low- or medium-boiling point alcohol,wherein the alcohol occupies at least 20% by weight of the total solventamount in the solvent system, and the molar ratio of the alcohol and theequivalent methylol unit of the aminoplast is at least 4:1;

the improved ARC composition having:

e. an ether or ester linkage derived from a poly(epoxide) molecule,

wherein the improved ARC prevents mixing of the resist/ARC components byvirtue of the thermosetting action of ARCs and provides an improvedoptical concentration in the target exposure and ARC layer thickness,and nullifies a need of a high molecular-weight thermoplastic ARC binderexhibiting a high solubility difference.

The above-mentioned ARC composition contains b. alkylated aminoplastcrosslinking agent derived from melamine, urea, benzoguanamine, orglycoluril, and c. protonic acid curing catalyst, and therefore providesa cured resist underlayer film. However, it is difficult to remove thecured resist underlayer film by a wet etching chemical liquid.

CITATION LIST Patent Literature

Patent Literature 1: JP H11-511194 A

SUMMARY OF INVENTION Technical Problem

A resist is applied onto a resist underlayer film, and subjected toexposure using a radiation (for example, an ArF excimer laser, a KrFexcimer laser, or an i-line) and development to obtain a desired resistpattern, and the resist underlayer film used in this case is required tohave such excellent resist solvent resistance that the film suffers nopeeling or damage due to a resist solvent. The resist underlayer film isfurther required to have such excellent resist developer resistance thatthe film suffers no peeling or damage due to a resist developer (aqueousalkali solution) mainly used in the resist development step. Further,for obtaining a desired resist pattern, the resist underlayer film isneeded to have such antireflection performance that the film cansuppress reflection from the substrate with respect to the radiationused in the lithography process to prevent the resist pattern fromdeteriorating due to a standing wave. Particularly, when the resistunderlayer film is removed by wet etching using a chemical liquid, theresist underlayer film is required to exhibit satisfactory solubility inthe wet etching chemical liquid such that the resist underlayer film canbe easily removed from the substrate.

On the other hand, in the wet etching chemical liquid for removing theresist and resist underlayer film, for reducing a damage to theprocessed substrate, an organic solvent is used. Further, for improvingthe removal properties for the resist and resist underlayer film, abasic organic solvent is used. However, it is difficult for theconventional technique to achieve a resist underlayer film which hasexcellent resistance to a resist solvent that is mainly an organicsolvent and to a resist developer that is an aqueous alkali solution,and which further exhibits removability only by a wet etching chemicalliquid, preferably solubility only in a wet etching chemical liquid. Anobject of the present invention is to solve the above-mentionedproblems.

Solution to Problem

The present invention encompasses the followings.

[1] A resist underlayer film-forming composition comprising a polymer(P) having a dicyanostyryl group or a compound (C) having adicyanostyryl group,

-   -   wherein the composition comprises a solvent,    -   wherein the composition is free from an alkylated aminoplast        crosslinking agent derived from melamine, urea, benzoguanamine,        or glycoluril, and    -   wherein the composition is free from a protonic acid curing        catalyst.

[2] The resist underlayer film-forming composition according to [1],wherein polymer (P) having a dicyanostyryl group or compound (C) havinga dicyanostyryl group is a reaction product of an active proton compoundand a polymer precursor (PP) containing an epoxy group or a compoundprecursor (PC) containing an epoxy group, respectively.

[3] The resist underlayer film-forming composition according to [1] or[2], wherein the dicyanostyryl group is represented by the followingformula (1):

wherein X represents an alkyl group, a hydroxy group, an alkoxy group,an alkoxycarbonyl group, a halogen atom, a cyano group, or a nitrogroup; R represents a hydrogen atom, an alkyl group, or an arylenegroup; n represents an integer of 0 to 4; and * indicates a bonding siteto part of polymer (P) or compound (C).

[4] The resist underlayer film-forming composition according to [1] or[2], wherein polymer (P) having a dicyanostyryl group or compound (C)having a dicyanostyryl group is represented by the following formula(2):

wherein Q is a group resulting from eliminating m quantity of end atomor atoms from the polymer or compound, wherein m is between 1 and anumber of repeating unit of the polymer when Q is the polymer, and m isan integer of 1 to 4 when Q is the compound,each of m quantity of A is independently a direct bond or an optionallybranched or substituted alkylene group having 1 to 10 carbon atomsoptionally interrupted with an ether linkage, a thioether linkage, or anester linkage,each of m quantity of B independently represents a direct bond, an etherlinkage, a thioether linkage, or an ester linkage,m quantity of R₁ represents a hydrogen atom, a methyl group, an ethylgroup, or a propyl group, and is optionally bonded to Q to form a ring,and each of m quantity of R₂ and R₃ independently represents a hydrogenatom, a methyl group, or an ethyl group, andeach of m quantity of L is independently represented by the followingformula (3):

wherein Y represents an ether linkage, a thioether linkage, or an esterlinkage,R represents a hydrogen atom, an alkyl group, or an arylene group,n represents an integer of 0 to 4, andeach of n quantity of X independently represents an alkyl group, ahydroxy group, an alkoxy group, an alkoxycarbonyl group, a halogen atom,a cyano group, or a nitro group.

[5] The resist underlayer film-forming composition according to any oneof [1] to [3], wherein polymer (P) having a dicyanostyryl group orcompound (C) having a dicyanostyryl group has an aromatic ring or analiphatic ring.

[6] The resist underlayer film-forming composition according to [4],wherein Q in formula (2) has an aromatic ring or an aliphatic ring.

[7] The resist underlayer film-forming composition according to [3] or[4], wherein R in formula (1) and/or formula (3) is a hydrogen atom.

[8] The resist underlayer film-forming composition according to [4],wherein Y in formula (3) represents an ether linkage or an esterlinkage.

[9] The resist underlayer film-forming composition according to any oneof [1] to [8], for use on a substrate having copper on the surface.

[10] An uncured resist underlayer film provided by removing a solventfrom an applied film comprising the resist underlayer film-formingcomposition according to any one of [1] to [9].

[11] The uncured resist underlayer film according to [10], which isformed on a substrate having copper on the surface.

[12] A method for producing a patterned substrate, comprising the stepsof:

applying the resist underlayer film-forming composition according to anyone of [1] to [9] onto a substrate having copper on the surface andremoving a solvent to form a resist underlayer film;

applying a resist onto the resist underlayer film and baking the appliedresist to form a resist film;

subjecting the semiconductor substrate covered with the resistunderlayer film and the resist to exposure; and

subjecting the resist film obtained after exposure to development andpatterning.

[13] A method for producing a semiconductor device, comprising the stepsof:

forming an uncured resist underlayer film comprising the resistunderlayer film-forming composition according to any one of [1] to [9]on a substrate having copper on the surface;

forming a resist film on the uncured resist underlayer film;

irradiating the resist film with a light or an electron beam andsubjecting the resultant resist film to development to form a resistpattern;

then removing the resist underlayer film exposed in the resist pattern;

performing copper plating in the formed resist pattern, preferably inthe resist pattern from which the resist underlayer film has beenremoved; and

removing the resist pattern and the resist underlayer film present underthe resist pattern.

[14] The method according to [13], wherein at least one of the steps ofremoving the resist underlayer film is conducted by a wet treatment.

Advantageous Effects of Invention

The resist underlayer film-forming composition of the present inventionis free from an alkylated aminoplast crosslinking agent derived frommelamine, urea, benzoguanamine, or glycoluril, and is free from aprotonic acid curing catalyst, and therefore the resist underlayer filmobtained from the composition is an uncured resist underlayer film. Theuncured resist underlayer film, however, exhibits a resist solventresistance and a developer resistance, especially when formed on asubstrate having copper on the surface. Therefore, the resist underlayerfilm-forming composition of the present invention can be applied to asemiconductor production process. For example, in the redistributionstep, the film on a copper substrate is subjected to lithography, andhence even an uncured resist underlayer film can be used. Further, theresist underlayer film-forming composition of the present invention isfree from the above-mentioned crosslinking agent and the above-mentionedcuring catalyst, and therefore has an advantage in that the film formedfrom the composition can be removed by a wet etching chemical liquid.

DESCRIPTION OF EMBODIMENTS

[Resist Underlayer Film-Forming Composition]

The resist underlayer film-forming composition of the present inventioncomprises polymer (P) having a dicyanostyryl group or compound (C)having a dicyanostyryl group, and a solvent, but is free from analkylated aminoplast crosslinking agent derived from melamine, urea,benzoguanamine, or glycoluril, and is free from a protonic acid curingcatalyst.

[Polymer (P) having a dicyanostyryl group or compound (C) having adicyanostyryl group]

The dicyanostyryl group in the present invention is a group representedby the following formula:

wherein X represents an alkyl group, a hydroxy group, an alkoxy group,an alkoxycarbonyl group, a halogen atom, a cyano group, or a nitrogroup; R represents a hydrogen atom, an alkyl group, or an arylenegroup; n represents an integer of 0 to 4; and * indicates a bonding siteto part of polymer (P) or compound (C).

In the resist underlayer film-forming composition of the presentinvention, the term “polymer” means a chemical substance havingrepeating structural units, including an oligomer, and the term“compound” means a chemical substance other than the polymer. The“polymer having a dicyanostyryl group” is preferably a polymer having adicyanostyryl group in the side chain of repeating structural units.

In the present invention, any polymer and compound having a site capableof having bonded a dicyanostyryl group by a known chemical reaction maybe used.

Polymer (P) having a dicyanostyryl group or compound (C) having adicyanostyryl group in the present invention is preferably a reactionproduct of polymer precursor (PP) containing an epoxy group or compoundprecursor (PC) containing an epoxy group and an active proton compoundhaving a dicyanostyryl group, or a reaction product obtained bysubjecting a reaction intermediate of polymer precursor (PP) containingan epoxy group or compound precursor (PC) containing an epoxy group andan active proton compound having a carbonyl group to cyanation(dicyanation).

The active proton compound in the present invention means a compoundimplied by the active proton compound, which is a term generally used inorganic chemistry, and is not particularly limited.

Examples of the active proton compounds include a compound having ahydroxy group, a compound having a carboxy group, a compound having athiol group, a compound having an amino group, and a compound having animide group, but preferred is a compound having a hydroxy group or acarboxy group.

Examples of the carbonyl group in the active proton compound having acarbonyl group include a formyl group (aldehyde group) and a ketonegroup, but preferred is a formyl group.

The dicyanostyryl group is preferably represented by the followingformula (1-1):

wherein R₁ to R₃ represent a hydrogen atom, a methyl group, or an ethylgroup,X represents an alkyl group, a hydroxy group, an alkoxy group, analkoxycarbonyl group, a cyano group, or a nitro group,Y represents an ether linkage, a thioether linkage, or an ester linkage,R represents a hydrogen atom, an alkyl group, or an arylene group,n represents an integer of 0 to 4, and ** indicates a bonding site topart of polymer (P) or compound (C).

Polymer (P) having a dicyanostyryl group or compound (C) having adicyanostyryl group preferably has an aromatic ring or an aliphaticring.

The aromatic ring in the present invention means a cyclic structurederived from:

(a) a monocyclic compound, such as benzene, phenol, or phloroglucinol,

(b) a fused ring compound, such as naphthalene or dihydroxynaphthalene,

(c) a heterocyclic compound, such as furan, thiophene, pyridine, orcarbazole,

(d) a compound obtained by bonding the aromatic ring of (a) to (c)through a single bond, such as biphenyl, phenylindole,9,9-bis(4-hydroxyphenyl)fluorene, orα,α,α′,α′-tetrakis(4-hydroxyphenyl)-p-xylene, or

(e) a compound obtained by linking the aromatic ring of (a) to (d)through a spacer, such as —(CH₂)_(n)— (n=1 to 20), —CH<, —CH═CH—, —C≡C—,—N═N—, —NH—, —NR—, —NHCO—, —NRCO—, —S—, —COO—, —O—, —CO—, or —CH═N—,such as phenylnaphthylamine.

Examples of aromatic compounds include benzene, thiophene, furan,pyridine, pyrimidine, pyrazine, pyrrole, oxazole, thiazole, imidazole,naphthalene, anthracene, quinoline, carbazole, quinazoline, purine,indolizine, benzothiophene, benzofuran, indole, phenylindole, andacridine.

Further, the above-mentioned aromatic compound may have at least onehydroxy group.

The aromatic compound having at least one hydroxy group is preferably aphenolic hydroxy group-containing compound.

Examples of phenolic hydroxy group-containing compounds include phenol,dihydroxybenzene, trihydroxybenzene, hydroxynaphthalene,dihydroxynaphthalene, trihydroxynaphthalene,tris(4-hydroxyphenyl)methane, tris(4-hydroxyphenyl)ethane,1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, and polynuclear phenols.

Examples of the polynuclear phenols include dihydroxybenzene,trihydroxybenzene, hydroxynaphthalene, dihydroxynaphthalene,trihydroxynaphthalene, tris(4-hydroxyphenyl)methane,tris(4-hydroxyphenyl)ethane, 2,2′-biphenol, and1,1,2,2-tetrakis(4-hydroxyphenyl)ethane.

The hydrogen atom of the above-mentioned aromatic compound may bereplaced by an alkyl group having 1 to 20 carbon atoms, a fused ringgroup, a heterocyclic group, a hydroxy group, an amino group, a nitrogroup, an ether group, an alkoxy group, a cyano group, or a carboxygroup.

The above-mentioned aromatic compound may be linked to another onethrough a single bond or a spacer.

Examples of spacers include —(CH₂)_(n)— (n=1 to 20), —CH<, —CH═CH—,—C≡C—, —N═N—, —NH—, —NR—, —NHCO—, —NRCO—, —S—, —COO—, —O—, —CO—, and—CH═N— and a combination thereof. Two or more spacers may be linkedtogether.

The aromatic compound preferably has at least one benzene ring,naphthalene ring, or triazine ring or a combination thereof.

The aliphatic ring in the present invention preferably has 4 or more, 6or more, 10 or less, or 8 or less carbon atoms. The aliphatic ring mayhave in the ring an atom other than carbon and hydrogen, for example,one atom or two or more atoms of oxygen, nitrogen, sulfur, a halogen, analkali metal, an alkaline earth metal, and a transition metal. Examplesof the rings include a cyclobutane ring, a cyclopentane ring, acyclohexane ring, a cycloheptane ring, a pyrrolidine ring, a piperidinering, a piperazine ring, a morpholine ring, a quinuclidine ring, ahydantoin ring, a triazine ring, and cyanuric acid.

R in formula (1-1) is preferably a hydrogen atom. X in formula (1-1)preferably represents an ether linkage or an ester linkage. In thepresent invention, the ester linkage includes —COO— and —OCO—.

Polymer (P) having a dicyanostyryl group or compound (C) having adicyanostyryl group is preferably represented by the following formula(2):

wherein Q is a group resulting from eliminating m quantity of end atomor atoms from the polymer or compound, wherein m is between 1 and anumber of repeating unit of the polymer when Q is the polymer, and m isan integer of 1 to 4 when Q is the compound,each of m quantity of A is independently a direct bond or an optionallybranched or substituted alkylene group having 1 to 10 carbon atomsoptionally interrupted with an ether linkage, a thioether linkage, or anester linkage,each of m quantity of B independently represents a direct bond, an etherlinkage, a thioether linkage, or an ester linkage,m quantity of R₁ represents a hydrogen atom, a methyl group, an ethylgroup, or a propyl group, and is optionally bonded to Q to form a ring,and each of m quantity of R₂ and R₃ independently represents a hydrogenatom, a methyl group, or an ethyl group, andeach of m quantity of L is independently represented by the followingformula (3):

wherein Y represents an ether linkage, a thioether linkage, or an esterlinkage,R represents a hydrogen atom, an alkyl group, or an arylene group,n represents an integer of 0 to 4, andeach of n quantity of X independently represents an alkyl group, ahydroxy group, an alkoxy group, an alkoxycarbonyl group, a halogen atom,a cyano group, or a nitro group.

Q in formula (2) preferably has an aromatic ring or an aliphatic ring. Rin formula (3) is preferably a hydrogen atom. Y in formula (3)preferably represents an ether linkage or an ester linkage.

Examples of the alkyl groups include linear or branched alkyl groupsoptionally having a substituent, and include a methyl group, an ethylgroup, a n-propyl group, an isopropyl group, a n-butyl group, asec-butyl group, a tert-butyl group, a n-pentyl group, an isopentylgroup, a neopentyl group, a n-hexyl group, an isohexyl group, a n-heptylgroup, a n-octyl group, a cyclohexyl group, a 2-ethylhexyl group, an-nonyl group, an isononyl group, a p-tert-butylcyclohexyl group, an-decyl group, a n-dodecylnonyl group, an undecyl group, a dodecylgroup, a tridecyl group, a tetradecyl group, a pentadecyl group, ahexadecyl group, a heptadecyl group, an octadecyl group, a nonadecylgroup, and an eicosyl group. Preferred are alkyl groups having 1 to 20carbon atoms, more preferred are alkyl groups having 1 to 12 carbonatoms, further preferred are alkyl groups having 1 to 8 carbon atoms,and most preferred are alkyl groups having 1 to 4 carbon atoms.

Examples of the alkoxy group include groups corresponding to theabove-mentioned alkyl groups having an oxygen atom bonded thereto.Examples include a methoxy group, an ethoxy group, a propoxy group, anda butoxy group.

Examples of the alkoxycarbonyl group include groups corresponding to theabove-mentioned alkyl groups having bonded thereto an oxygen atom and acarbonyl group. Examples include a methoxycarbonyl group, anethoxycarbonyl group, a propoxycarbonyl group, and a butoxycarbonylgroup.

Examples of the alkylene group include divalent groups corresponding tothe above-mentioned alkyl groups having further removed therefrom ahydrogen atom.

Examples include a methylene group, an ethylene group, a 1,3-propylenegroup, and a 1,2-propylene group.

Examples of the arylene groups include a phenylene group, ano-methylphenylene group, a m-methylphenylene group, a p-methylphenylenegroup, an α-naphthylene group, a β-naphthylene group, an o-biphenylylenegroup, a m-biphenylylene group, a p-biphenylylene group, a 1-anthrylenegroup, a 2-anthrylene group, a 9-anthrylene group, a 1-phenanthrylenegroup, a 2-phenanthrylene group, a 3-phenanthrylene group, a4-phenanthrylene group, and a 9-phenanthrylene group. Preferred arearylene groups having 6 to 14 carbon atoms, and more preferred arearylene groups having 6 to 10 carbon atoms.

The halogen atom generally indicates an atom of each of fluorine,chlorine, bromine, and iodine.

Specific examples of polymer (P) having a dicyanostyryl group orcompound (C) having a dicyanostyryl group include the followings.

In the above formulae, L₁ means:

[Preparation of polymer (P) having a dicyanostyryl group or compound (C)having a dicyanostyryl group]

The above-mentioned polymer (P) having a dicyanostyryl group or compound(C) having a dicyanostyryl group may be obtained by the two methodsdescribed below.

(Synthesis method 1 for polymer (P) having a dicyanostyryl group orcompound (C) having a dicyanostyryl group)

The above-mentioned polymer (P) having a dicyanostyryl group or compound(C) having a dicyanostyryl group may be obtained by reacting polymerprecursor (PP) containing an epoxy group or compound precursor (PC)containing an epoxy group and an active proton compound having adicyanostyryl group by a known method.

The active proton compound having a dicyanostyryl group is obtained bysubjecting an active proton compound having a carbonyl group tocyanation. An example of the synthesis scheme is shown below.

Explanation is made taking compound (C) having a dicyanostyryl group asan example. The synthesis method comprises the step of reacting anactive proton compound having a dicyanostyryl group and compoundprecursor (PC) having an epoxy group. An example of the synthesis schemein the case where compound (C) is a heterocyclic compound is shownbelow.

(Synthesis method 2 for polymer (P) having a dicyanostyryl group orcompound (C) having a dicyanostyryl group)

The synthesis method comprises the steps of: reacting compound precursor(PC) or polymer precursor (PP) having an epoxy group and an activeproton compound having a carbonyl group to obtain an intermediatecompound or intermediate polymer; and subjecting the obtainedintermediate to cyanation (dicyanation) according to, for example, theabove-mentioned method. An example of the synthesis scheme in the casewhere the compound of compound precursor (PC) having an epoxy group is aheterocyclic compound is shown below.

Polymer precursor (PP) having an epoxy group or compound precursor (PC)having an epoxy group in the present invention includes, for example,the following formulae (B-1) to (B-36), but the polymer precursor orcompound precursor is not limited to these formulae.

In formula (B-17), each of a, b, c, and d is 0 or 1, and the equation:a+b+c+d=1 is satisfied.

The active proton compound having a carbonyl group in the presentinvention includes, for example, the following formulae (C-1) to (C-40),but the compound is not limited to these formulae.

Examples of catalysts used in the reaction for activating the epoxygroup include quaternary phosphonium salts, such asethyltriphenylphosphonium bromide and tetrabutylphosphonium bromide, andquaternary ammonium salts, such as benzyltriethylammonium chloride. Theamount of the catalyst used is generally within the range of 0.001 to 1equivalent, relative to 1 equivalent of the epoxy group.

The above-mentioned reaction may be conducted without using a solvent,but is generally conducted using a solvent. Any solvent may be used aslong as it does not inhibit the reaction. Examples of solvents includeethers, such as 1,2-dimethoxyethane, diethylene glycol dimethyl ether,propylene glycol monomethyl ether, propylene glycol monomethyl etheracetate, tetrahydrofuran, and dioxane.

The reaction temperature is generally within the range of 40 to 200° C.The reaction time is appropriately selected depending on the reactiontemperature, but is generally within the range of about 30 minutes to 50hours.

The compound obtained as mentioned above generally has a weight averagemolecular weight Mw of 200 to 3,000, or 500 to 2,000. Similarly, theobtained polymer generally has a weight average molecular weight Mw of1,000 to 20,000, or 2,000 to 10,000.

[Solvent]

With respect to the solvent for the resist underlayer film-formingcomposition of the present invention, there is no particular limitationas long as it is a solvent which can dissolve therein theabove-mentioned polymer (P) having a dicyanostyryl group or compound (C)having a dicyanostyryl group and other components, and any of suchsolvents may be used. Particularly, the resist underlayer film-formingcomposition of the present invention is used in a uniform solutionstate, and therefore, taking the application properties of thecomposition into consideration, it is recommended that a solventgenerally used in a lithography process should be also used.

Examples of such solvents include methyl cellosolve acetate, ethylcellosolve acetate, propylene glycol, propylene glycol monomethyl ether,propylene glycol monoethyl ether, methylisobutyl carbinol, propyleneglycol monobutyl ether, propylene glycol monomethyl ether acetate,propylene glycol monoethyl ether acetate, propylene glycol monopropylether acetate, propylene glycol monobutyl ether acetate, toluene,xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethylethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate,methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl3-ethoxypropionate, methyl 3-ethoxypropionate, methyl pyruvate, ethylpyruvate, ethylene glycol monomethyl ether, ethylene glycol monoethylether, ethylene glycol monopropyl ether, ethylene glycol monobutylether, ethylene glycol monomethyl ether acetate, ethylene glycolmonoethyl ether acetate, ethylene glycol monopropyl ether acetate,ethylene glycol monobutyl ether acetate, diethylene glycol dimethylether, diethylene glycol diethyl ether, diethylene glycol dipropylether, diethylene glycol dibutyl ether, propylene glycol monomethylether, propylene glycol dimethyl ether, propylene glycol diethyl ether,propylene glycol dipropyl ether, propylene glycol dibutyl ether, ethyllactate, propyl lactate, isopropyl lactate, butyl lactate, isobutyllactate, methyl formate, ethyl formate, propyl formate, isopropylformate, butyl formate, isobutyl formate, amyl formate, isoamyl formate,methyl acetate, ethyl acetate, amyl acetate, isoamyl acetate, hexylacetate, methyl propionate, ethyl propionate, propyl propionate,isopropyl propionate, butyl propionate, isobutyl propionate, methylbutyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butylbutyrate, isobutyl butyrate, ethyl hydroxyacetate, ethyl2-hydroxy-2-methylpropionate, methyl 3-methoxy-2-methylpropionate,methyl 2-hydroxy-3-methylbutyrate, ethyl methoxyacetate, ethylethoxyacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate,ethyl 3-methoxypropionate, 3-methoxybutyl acetate, 3-methoxypropylacetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate,toluene, xylene, methyl ethyl ketone, methyl propyl ketone, methyl butylketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone,N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide,N-methylpyrrolidone, 4-methyl-2-pentanol, and γ-butyrolactone. Thesesolvents may be used each alone or in combination of two or more.

Preferred are, for example, propylene glycol monomethyl ether, propyleneglycol monomethyl ether acetate, ethyl lactate, butyl lactate, andcyclohexanone. Especially preferred are propylene glycol monomethylether and propylene glycol monomethyl ether acetate.

[Crosslinking Agent]

The resist underlayer film-forming composition of the present inventionis free from an alkylated aminoplast crosslinking agent derived frommelamine, urea, benzoguanamine, or glycoluril.

More specifically, the resist underlayer film-forming composition of thepresent invention is free from a crosslinking agent having at least twocrosslink-forming substituents, for example, a compound, such asmethoxymethylated glycoluril, butoxymethylated glycoluril,methoxymethylated melamine, butoxymethylated melamine, methoxymethylatedbenzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea,butoxymethylated urea, or methoxymethylated thiourea. Further, theresist underlayer film-forming composition of the present invention isfree from a condensation product of the above compound.

It is preferred that the resist underlayer film-forming composition ofthe present invention is free from a crosslinking agent containing inthe molecule thereof a crosslink-forming substituent having an aromaticring (for example, a benzene ring or a naphthalene ring).

Examples of the crosslinking agent that is not contained in the resistunderlayer film-forming composition of the present invention includecompounds having a partial structure of formula (4) below, and polymersor oligomers having repeating units of formula (5) below.

The above-shown R_(a), R_(b), R_(c), and R_(d) are a hydrogen atom or analkyl group having 1 to 10 carbon atoms. Each of na, nb, nc, and ndrepresents an integer of 0 to 3. With respect to the alkyl group, thosementioned above as examples of alkyl groups may be used.

Examples of the compounds, polymers, and oligomers of formulae (4) and(5) are shown below.

[Protonic Acid Curing Catalyst]

Accordingly, the resist underlayer film-forming composition of thepresent invention is free from a protonic acid curing catalyst that isgenerally used together with the above-mentioned crosslinking agent.

Examples of the protonic acid curing catalyst that is not contained inthe resist underlayer film-forming composition of the present inventioninclude mineral acid, sulfonic acid compounds (for example,p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridiniump-toluenesulfonate, 4-phenolsulfonic acid, camphorsulfonic acid,4-chlorobenzenesulfonic acid, benzenedisulfonic acid, and1-naphthalenesulfonic acid), oxalic acid, maleic acid, hexamine acid,phthalic acid, salicylic acid, 5-sulfosalicylic acid, citric acid,benzoic acid, hydroxybenzoic acid, naphthalenecarboxylic acid, and amixture thereof.

Further, it is preferred that the resist underlayer film-formingcomposition of the present invention is free from an acid generator.Examples of the acid generator that is not contained in the resistunderlayer film-forming composition of the present invention include athermal acid generator and a photo-acid generator.

Examples of the thermal acid generator that is not contained in theresist underlayer film-forming composition of present invention include2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyltosylate, and other organic sulfonic acid alkyl esters.

Examples of the photo-acid generator that is not contained in the resistunderlayer film-forming composition of the present invention include anonium salt compound, a sulfonimide compound, and adisulfonyldiazomethane compound.

Further, it is preferred that the resist underlayer film-formingcomposition of the present invention is free from an onium saltcompound. Examples of the onium salt compound that is not contained inthe resist underlayer film-forming composition of the present inventioninclude iodonium salt compounds, such as diphenyliodoniumhexafluorophosphate, diphenyliodonium trifluoromethanesulfonate,diphenyliodonium nonafluoronormalbutanesulfonate, diphenyliodoniumperfluoronormaloctanesulfonate, diphenyliodonium camphorsulfonate,bis(4-tert-butylphenyl)iodonium camphorsulfonate, andbis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate, and sulfoniumsalt compounds, such as triphenylsulfonium hexafluoroantimonate,triphenylsulfonium nonafluoronormalbutanesulfonate, triphenylsulfoniumcamphorsulfonate, and triphenylsulfonium trifluoromethanesulfonate.

Further, it is preferred that the resist underlayer film-formingcomposition of the present invention is free from a sulfonimidecompound. Examples of the sulfonimide compound that is not contained inthe resist underlayer film-forming composition of the present inventioninclude N-(trifluoromethanesulfonyloxy)succinimide,N-(nonafluoronormalbutanesulfonyloxy)succinimide, N-(camphorsulfonylox)succinimide, and N-(trifluoromethanesulfonyloxy)naphthalimide.

Further, it is preferred that the resist underlayer film-formingcomposition of the present invention is free from adisulfonyldiazomethane compound. Examples of the disulfonyldiazomethanecompound that is not contained in the resist underlayer film-formingcomposition of the present invention includebis(trifluoromethylsulfonyl)diazomethane,bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane,bis(p-toluenesulfonyl)diazomethane,bis(2,4-dimethylbenzenesulfonyl)diazomethane, andmethylsulfonyl-p-toluenesulfonyldiazomethane.

In the resist underlayer film-forming composition of the presentinvention, when the above-mentioned polymer (P) having a dicyanostyrylgroup or compound (C) having a dicyanostyryl group is a reaction productof polymer precursor (PP) containing an epoxy group or compoundprecursor (PC) containing an epoxy group and an active proton compound,the resist underlayer film-forming composition is free from theunreacted active proton compound (for example, a compound having acarboxylic acid). When there is a possibility that the unreacted activeproton compound is present, the unreacted active proton compound may beremoved by a known method.

[Other Components]

In the resist underlayer film-forming composition of the presentinvention, for further improving the application properties to preventthe occurrence of pinhole or striation and uneven surface, a surfactantmay be incorporated into the composition. Examples of surfactantsinclude nonionic surfactants, e.g., polyoxyethylene alkyl ethers, suchas polyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether;polyoxyethylene alkyl aryl ethers, such as polyoxyethylene octylphenolether and polyoxyethylene nonylphenol ether;polyoxyethylene-polyoxypropylene block copolymers; sorbitan fatty acidesters, such as sorbitan monolaurate, sorbitan monopalmitate, sorbitanmonostearate, sorbitan monooleate, sorbitan trioleate, and sorbitantristearate; and polyoxyethylene sorbitan fatty acid esters, such aspolyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate, and polyoxyethylene sorbitan tristearate, fluorinesurfactants, such as EFTOP EF301, EF303, EF352 (trade name, manufacturedby Tohchem Products Co., Ltd.), MEGAFACE F171, F173, R-30N, R-40, R-40N,R-40LM (trade name, manufactured by DIC Corporation), Fluorad FC430,FC431 (trade name, manufactured by Sumitomo 3M), AsahiGuard AG710,Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (trade name,manufactured by AGC Inc.), and organosiloxane polymer KP341(manufactured by Shin-Etsu Chemical Co., Ltd.). The amount of thesurfactant incorporated is generally within the range of 2.0% by mass orless, preferably 1.0% by mass or less, based on the mass of the solidsof the resist underlayer film material. These surfactants may be usedeach alone or in combination of two or more. When a surfactant is used,the amount of the surfactant is within the range of 0.0001 to 5 parts bymass, or 0.001 to 1 part by mass, or 0.01 to 0.5 part by mass, relativeto 100 parts by mass of the solids of the resist underlayer film-formingcomposition.

In the resist underlayer film-forming composition of the presentinvention, for example, a light absorber, a rheology modifier, or abonding auxiliary may be added. The rheology modifier is effective inimproving the fluidity of the resist underlayer film-formingcomposition. The bonding auxiliary is effective in improving theadhesion between a semiconductor substrate or a resist and the resistunderlayer film.

With respect to the light absorber, for example, a commerciallyavailable light absorber described in “Kougyo-you Shikiso no Gijutsu toShijou (Techniques and Markets of Industrial Dyes)” (CMC Publishing Co.,Ltd.) or “Senryo Binran (Dye Handbook)” (edited by The Society ofSynthetic Organic Chemistry, Japan), for example, C. I. Disperse Yellow1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82,88, 90, 93, 102, 114, and 124; C. I. Disperse Orange 1, 5, 13, 25, 29,30, 31, 44, 57, 72, and 73; C. I. Disperse Red 1, 5, 7, 13, 17, 19, 43,50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; C. I. DisperseViolet 43; C. I. Disperse Blue 96; C. I. Fluorescent Brightening Agent112, 135, and 163; C. I. Solvent Orange 2 and 45; C. I. Solvent Red 1,3, 8, 23, 24, 25, 27, and 49; C. I. Pigment Green 10; and C. I. PigmentBrown 2 may be preferably used. The light absorber is generallyincorporated in an amount of 10% by mass or less, preferably 5% by massor less, based on the mass of the solids of the resist underlayerfilm-forming composition.

A rheology modifier is added mainly for the purpose of improving thefluidity of the resist underlayer film-forming composition, particularlyfor improving the uniformity of the thickness of the resist underlayerfilm or the filling of the inside of hole with the resist underlayerfilm-forming composition in the baking step. Specific examples ofrheology modifiers include phthalic acid derivatives, such as dimethylphthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate,and butylisodecyl phthalate; adipic acid derivatives, such asdinormalbutyl adipate, diisobutyl adipate, diisooctyl adipate, andoctyldecyl adipate; maleic acid derivatives, such as dinormalbutylmaleate, diethyl maleate, and dinonyl maleate; oleic acid derivatives,such as methyl oleate, butyl oleate, and tetrahydrofurfuryl oleate; andstearic acid derivatives, such as normalbutyl stearate and glycerylstearate. The rheology modifier is generally incorporated in an amountof less than 30% by mass, based on the mass of the solids of the resistunderlayer film-forming composition.

A bonding auxiliary is added mainly for the purpose of improving theadhesion between a substrate or a resist and the resist underlayerfilm-forming composition to prevent the resist from peeling offparticularly in the development. Specific examples of bondingauxiliaries include chlorosilanes, such as trimethylchlorosilane,dimethylmethylolchlorosilane, methyldiphenylchlorosilane, andchloromethyldimethylchlorosilane; alkoxysilanes, such astrimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane,dimethylmethylolethoxysilane, diphenyldimethoxysilane, andphenyltriethoxysilane; silazanes, such as hexamethyldisilazane,N,N′-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, andtrimethylsilylimidazole; silanes, such as methyloltrichlorosilane,γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, andγ-glycidoxypropyltrimethoxysilane; heterocyclic compounds, such asbenzotriazole, benzimidazole, indazole, imidazole,2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole,urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and ureaor thiourea compounds, such as 1,1-dimethylurea and 1,3-dimethylurea.The bonding auxiliary is generally incorporated in an amount of lessthan 5% by mass, preferably less than 2% by mass, based on the mass ofthe solids of the resist underlayer film-forming composition.

The resist underlayer film-forming composition of the present inventiongenerally has a solid content of 0.1 to 70% by mass, preferably 0.1 to60% by mass. The solid content indicates a content of the solidsremaining after removing the solvent from the all components of theresist underlayer film-forming composition. The proportion of the totalof the above-mentioned polymer (P) and compound (C) in the solids iswithin the range of 1 to 100% by mass, 50 to 100% by mass, and 80 to100% by mass with increasing preference.

One measure for evaluating whether the resist underlayer film-formingcomposition is in a uniform solution state is to observe the passingproperty of the composition through a specific microfilter. The resistunderlayer film-forming composition of the present invention can passthrough a microfilter having a pore diameter of 0.1 μm and is in auniform solution state.

Examples of materials for the microfilter include fluororesins, such asPTFE (polytetrafluoroethylene) and PFA(tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PE(polyethylene), UPE (ultra-high molecular weight polyethylene), PP(polypropylene), PSF (polysulfone), PES (polyether sulfone), and nylon,and a microfilter made of PTFE (polytetrafluoroethylene) is preferred.

[Substrate]

In the present invention, examples of substrates used in the productionof a semiconductor device include a silicon wafer substrate, asilicon/silicon dioxide coated substrate, a silicon nitride substrate, aglass substrate, an ITO substrate, a polyimide substrate, and a lowpermittivity material (low-k material) coated substrate.

Recently, in the field of three-dimensional mounting for semiconductorproduction process, for the purpose of reducing the length of a wiringbetween semiconductor chips to increase the response and save the powerconsumption, the application of a FOWLP process is spreading. In the RDL(redistribution layer) step for forming a wiring between semiconductorchips, copper (Cu) is used as a wiring member, and, as the copper wiringis becoming finer, the application of an antireflection film (resistunderlayer film-forming composition) is needed. The resist underlayerfilm-forming composition of the present invention may be advantageouslyapplied to a substrate having copper on the surface.

[Resist Underlayer Film and Method for Producing a Semiconductor Device]

Hereinbelow, the resist underlayer film using the resist underlayerfilm-forming composition of the present invention and the method forproducing a semiconductor device are described.

The resist underlayer film-forming composition of the present inventionis applied onto the above-mentioned substrate used in the production ofa semiconductor device (for example, a substrate having copper on thesurface) by an appropriate application method, such as a spinner or acoater, and then a solvent is removed to form a resist underlayer film.

Conditions for removing the solvent are appropriately selected fromthose at a temperature of 80 to 400° C. for a time of 0.3 to 60 minutes.Preferred conditions for removing the solvent are those at a temperatureof 150 to 350° C. for a time of 0.5 to 2 minutes. The thickness of theformed resist underlayer film is, for example, within the range of 10 to1,000 nm, or 20 to 500 nm, or 30 to 400 nm, or 50 to 300 nm.

The resist underlayer film-forming composition of the present inventionis free from an alkylated aminoplast crosslinking agent derived frommelamine, urea, benzoguanamine, or glycoluril, and is free from aprotonic acid curing catalyst, and therefore the resist underlayer filmformed from the composition is an uncured resist underlayer film.

An inorganic resist underlayer film (hard mask) may be formed on theorganic resist underlayer film of the present invention. For example, aninorganic resist underlayer film may be formed by spin coating thesilicon-containing resist underlayer film (inorganic resist underlayerfilm) forming composition described in WO2009/104552A1, or a Siinorganic material film may be formed by, for example, a CVD method.

Then, a resist film, for example, a layer of photoresist is formed onthe uncured resist underlayer film. The layer of photoresist may beformed by a known method, namely, by applying a photoresist compositionsolution onto the resist underlayer film and baking the appliedcomposition. The thickness of the photoresist is, for example, withinthe range of 50 to 10,000 nm, or 100 to 2,000 nm.

With respect to the photoresist formed on the uncured resist underlayerfilm, there is no particular limitation as long as it is sensitive to alight used in the exposure. Any of a negative photoresist and a positivephotoresist may be used. They include, for example, a positivephotoresist comprising a novolak resin and1,2-naphthoquinonediazidosulfonate; a chemical amplification photoresistcomprising a photo-acid generator and a binder having a group that isdecomposed due to an acid to increase the alkali solubility; a chemicalamplification photoresist comprising an alkali-soluble binder, aphoto-acid generator, and a low-molecular weight compound that isdecomposed due to an acid to increase the alkali solubility of thephotoresist; and a chemical amplification photoresist comprising aphoto-acid generator, a binder having a group that is decomposed due toan acid to increase the alkali solubility, and a low-molecular weightcompound that is decomposed due to an acid to increase the alkalisolubility of the photoresist. For example, they include trade name:APEX-E, manufactured by Shipley Company, Inc., trade name: PAR710,manufactured by Sumitomo Chemical Co., Ltd., and trade name: SEPR430,manufactured by Shin-Etsu Chemical Co., Ltd. Further, there can bementioned fluorine atom-containing polymer photoresists described in,for example, Proc. SPIE, Vol. 3999, 330-334 (2000), Proc. SPIE, Vol.3999, 357-364 (2000), and Proc. SPIE, Vol. 3999, 365-374 (2000).

Next, a resist pattern is formed by irradiation with a light or anelectron beam and development. Exposure through a predetermined mask isfirst conducted. In the exposure, for example, a near ultraviolet light,a far ultraviolet light, or an extreme ultraviolet light (for example,an EUV (wavelength: 13.5 nm)) is used. Specifically, for example, ani-line (wavelength: 365 nm), a KrF excimer laser (wavelength: 248 nm),an ArF excimer laser (wavelength: 193 nm), or an F₂ excimer laser(wavelength: 157 nm) may be used. Of these, an i-line (wavelength: 365nm) is preferred. After the exposure, if necessary, post exposure bakemay be performed. The post exposure bake is performed under conditionsappropriately selected from those at a heating temperature of 70 to 150°C. for a heating time of 0.3 to 10 minutes.

Further, in the present invention, as a resist, instead of thephotoresist, a resist for electron beam lithography may be used. Any ofa negative electron beam resist and a positive electron beam resist maybe used. They include, for example, a chemical amplification resistcomprising an acid generator and a binder having a group that isdecomposed due to an acid to change the alkali solubility; a chemicalamplification resist comprising an alkali-soluble binder, an acidgenerator, and a low-molecular weight compound that is decomposed due toan acid to change the alkali solubility of the resist; a chemicalamplification resist comprising an acid generator, a binder having agroup that is decomposed due to an acid to change the alkali solubility,and a low-molecular weight compound that is decomposed due to an acid tochange the alkali solubility of the resist; a non-chemical amplificationresist comprising a binder having a group that is decomposed due to anelectron beam to change the alkali solubility; and a non-chemicalamplification resist comprising a binder having a site that suffersbreakage due to an electron beam to change the alkali solubility. Alsowhen using the above electron beam resist, a resist pattern may besimilarly formed as in the case where a photoresist is used and anelectron beam is used as a source of irradiation.

Then, development using a developer is conducted. In the development,for example, when a positive photoresist is used, the exposed portion ofthe photoresist is removed, so that a photoresist pattern is formed.

Examples of developers include alkaline aqueous solutions, e.g., aqueoussolutions of an alkali metal hydroxide, such as potassium hydroxide orsodium hydroxide, aqueous solutions of a quaternary ammonium hydroxide,such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, orcholine, and aqueous solutions of an amine, such as ethanolamine,propylamine, or ethylenediamine. Further, for example, a surfactant maybe added to the above developer. Conditions for the development areappropriately selected from those at a temperature of 5 to 50° C. for atime of 10 to 600 seconds.

In the present invention, an organic underlayer film (lower layer) isformed on a substrate, and then an inorganic underlayer film(intermediate layer) is formed on the organic underlayer film, and theresultant film may be covered with a photoresist (upper layer). Byvirtue of this, even when a substrate is covered with a photoresisthaving a smaller thickness for preventing an occurrence of patterncollapse due to a reduced pattern width of the photoresist, appropriateselection of an etching gas enables processing of the substrate. Forexample, processing of the resist underlayer film may be made by usingas an etching gas a fluorine-based gas having an etching rate that issatisfactorily faster than that for the photoresist; processing of thesubstrate may be made by using as an etching gas a fluorine-based gashaving an etching rate that is satisfactorily faster than that for theinorganic underlayer film; and further, processing of the substrate maybe made by using as an etching gas an oxygen-based gas having an etchingrate that is satisfactorily faster than that for the organic underlayerfilm.

Subsequently, using the thus formed photoresist pattern as a protectivefilm, the inorganic underlayer film is removed, and then, using a filmcomprising the patterned photoresist and inorganic underlayer film as aprotective film, the organic underlayer film is removed. Finally, usingthe patterned inorganic underlayer film and organic underlayer film as aprotective film, processing of the semiconductor substrate is performed.

First, a portion of the inorganic underlayer film, from which thephotoresist has been removed, is removed by dry etching so as to exposethe semiconductor substrate. In the dry etching for the inorganicunderlayer film, for example, a gas of tetrafluoromethane (CF₄),perfluorocyclobutane (C₄F₈), perfluoropropane (CSFs), trifluoromethane,carbon monoxide, argon, oxygen, nitrogen, sulfur hexafluoride,difluoromethane, nitrogen trifluoride, chlorine trifluoride, chlorine,trichloroborane, or dichloroborane may be used. In the dry etching forthe inorganic underlayer film, a halogen-based gas is preferably used,and a fluorine-based gas is more preferably used. Examples offluorine-based gases include tetrafluoromethane (CF₄),perfluorocyclobutane (C₄F₈), perfluoropropane (C₃F₈), trifluoromethane,and difluoromethane (CH₂F₂).

Then, using a film comprising the patterned photoresist and inorganicunderlayer film as a protective film, the organic underlayer film isremoved.

The inorganic underlayer film containing silicon atoms in a large amountis unlikely to be removed by dry etching using an oxygen-based gas, andtherefore the organic underlayer film is often removed by dry etchingusing an oxygen-based gas.

Finally, processing of the semiconductor substrate is conducted. Theprocessing of the semiconductor substrate is preferably conducted by dryetching using a fluorine-based gas.

Examples of fluorine-based gases include tetrafluoromethane (CF₄),perfluorocyclobutane (C₄F₈), perfluoropropane (C₃F₈), trifluoromethane,and difluoromethane (CH₂F₂).

Further, before forming the photoresist, an organic antireflection filmmay be formed on the uncured resist underlayer film as an upper layer.With respect to the antireflection film composition used in forming theantireflection film, there is no particular limitation, and anyantireflection film composition may be selected from those which havebeen commonly used in a lithography process. An antireflection film maybe formed by a method commonly used, for example, by applying thecomposition using a spinner or a coater and baking it.

The uncured resist underlayer film formed from the resist underlayerfilm-forming composition may have an absorption with respect to thelight used in a lithography process depending on the wavelength of thelight. In such a case, the uncured resist underlayer film may functionas an antireflection film having an effect of preventing a lightreflected from the substrate. Further, the resist underlayer film formedfrom the resist underlayer film-forming composition of the presentinvention may function as a hard mask. The resist underlayer film of thepresent invention may also be used as, for example, a layer forpreventing an interaction between a substrate and a photoresist; a layerhaving a function of preventing an adverse effect on a substrate of thematerial used in a photoresist or a substance formed during the exposurefor the photoresist; a layer having a function of preventing a substancegenerated from a substrate upon heating or baking from diffusing into aphotoresist as an upper layer; and a barrier layer for reducing thephotoresist layer poisoning effect of a semiconductor substratedielectric layer.

Meanwhile, for the purpose of simplifying the steps for process,reducing a damage to the substrate, and reducing the cost, a method ofremoving the resist underlayer film by wet etching using a chemicalliquid, instead of dry etching, has been studied. However, the resistunderlayer film formed from a conventional resist underlayerfilm-forming composition is inherently required to be a cured filmhaving a solvent resistance for suppressing mixing of the resistunderlayer film and the resist being applied. Further, the resistunderlayer film must have a resistance to a developer, which isnecessarily used to develop the resist when patterning the resist.Therefore, it is difficult for the conventional technique to achievesuch a resist underlayer film-forming composition that the cured filmobtained from the composition is insoluble in a resist solvent and adeveloper and soluble only in a wet etching liquid. However, the resistunderlayer film-forming composition of the present invention can providea resist underlayer film, which is soluble in a wet etching liquid.

The wet etching liquid preferably contains, for example, an organicsolvent, and may contain an acidic compound or a basic compound.Examples of organic solvents include dimethyl sulfoxide,dimethylformamide, dimethylacetamide, N-methylpyrrolidone,N-ethylpyrrolidone, ethylene glycol, propylene glycol, and diethyleneglycol dimethyl ether. Examples of acidic compounds include inorganicacids and organic acids, and examples of inorganic acids includehydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; andexamples of organic acids include p-toluenesulfonic acid,trifluoromethanesulfonic acid, salicylic acid, 5-sulfosalicylic acid,4-phenolsulfonic acid, camphorsulfonic acid, 4-chlorobenzenesulfonicacid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, acetic acid,propionic acid, trifluoroacetic acid, citric acid, benzoic acid,hydroxybenzoic acid, and naphthalenecarboxylic acid. Examples of basiccompounds include inorganic bases and organic bases; and examples ofinorganic bases include alkali metal hydroxides, such as sodiumhydroxide and potassium hydroxide, quaternary ammonium hydroxides, suchas tetramethylammonium hydroxide, tetraethylammonium hydroxide, andcholine, and amines, such as ethanolamine, propylamine,diethylaminoethanol, and ethylenediamine. In the wet etching liquid,only one type of an organic solvent may be used, or two or more types oforganic solvents may be used in combination. Further, only one type ofan acidic compound or basic compound may be used, or two or more typesof acidic compounds or basic compounds may be used in combination. Theamount of the acidic compound or basic compound incorporated is withinthe range of 0.01 to 20% by weight, preferably 0.1 to 5% by weight,especially preferably 0.2 to 1% by weight, based on the weight of thewet etching liquid. With respect to the wet etching liquid, preferred isan organic solvent containing a basic compound, and especially preferredis a mixture containing dimethyl sulfoxide and tetramethylammoniumhydroxide.

Recently, in the field of three-dimensional mounting for semiconductorproduction process, the application of a FOWLP (Fan-Out Wafer LevelPackage) process has been spreading, and, in the RDL (redistributionlayer) step for forming a copper wiring, a resist underlayer film may beapplied.

The resist underlayer film used in a representative RDL step isdescribed below, but is not limited to the description. A photosensitiveinsulating film is first formed on a semiconductor chip, and thensubjected to patterning by irradiation with a light (exposure) anddevelopment so that a semiconductor chip electrode portion is opened.Subsequently, a copper seed layer for forming a copper wiring as awiring member in the plating step is formed by sputtering. Then, aresist underlayer film and a photoresist layer are successively formed,and then subjected to irradiation with a light and development toperform patterning of the resist. The unnecessary resist underlayer filmis removed by dry etching, and the exposed copper seed layer in theresist pattern is subjected to copper electroplating to form a copperwiring constituting a first wiring layer. Further, the unnecessaryresist, resist underlayer film, and copper seed layer are removed by dryetching or wet etching or both of them. The formed copper wiring layeris further coated with an insulating film, and then a copper seed layer,a resist underlayer film, and a resist are formed in this order, andpatterning of the resist, removal of the resist underlayer film, andcopper plating are conducted to form a second copper wiring layer. Theabove steps are repeated to form an intended copper wiring, and then abump for taking out an electrode is formed.

The resist underlayer film-forming composition of the present inventionis advantageous in that the resist underlayer film obtained from thecomposition can be removed by wet etching, and therefore, from theviewpoint of simplifying the steps for process and reducing a damage tothe processed substrate, the resist underlayer film-forming compositionof the present invention can be especially advantageously used for aresist underlayer film in the RDL step.

EXAMPLES

Hereinbelow, the present invention will be described in detail withreference to the following Examples, which should not be construed aslimiting the scope of the present invention.

The apparatus and other conditions used in the measurement of the weightaverage molecular weight of the polymers obtained in the followingSynthesis Examples are shown below.Apparatus: HLC-8320GPC, manufactured by Tosoh Corp.GPC Column: Shodex [registered trademark]-Asahipak [registeredtrademark] (Showa Denko K.K.)Column temperature: 40° C.Flow rate: 0.35 mL/minute

Eluent: Tetrahydrofuran (THF)

Standard sample: Polystyrene (Tosoh Corp.)

Synthesis Example 1

15.00 g of a phenolic novolak epoxy resin (product name: DEN,manufactured by The Dow Chemical Company; epoxy functionality: 5.55eq./kg), 10.17 g of 4-hydroxybenzaldehyde, 1.41 g oftetrabutylphosphonium bromide, and 39.87 g of propylene glycolmonomethyl ether were placed in a reaction flask and heated under refluxin a nitrogen gas atmosphere for 24 hours. Subsequently, a solutionprepared by dissolving 5.50 g of malononitrile in 34.99 g of propyleneglycol monomethyl ether was added to the system, and the resultantmixture was further heated under reflux for 4 hours. The obtainedreaction product, which corresponds to formula (A-1), had a weightaverage molecular weight Mw of 2,100, as determined by GPC using aconversion calibration curve obtained from the standard polystyrene.

Synthesis Example 2

12.00 g of a phenolic novolak epoxy resin (product name: DEN,manufactured by The Dow Chemical Company; epoxy functionality: 5.55eq./kg), 4.07 g of 4-hydroxybenzaldehyde, 5.00 of terephthalaldehydicacid, 1.13 g of tetrabutylphosphonium bromide, and 33.30 g of propyleneglycol monomethyl ether were placed in a reaction flask and heated underreflux in a nitrogen gas atmosphere for 23 hours. Subsequently, asolution prepared by dissolving 4.40 g of malononitrile in 28.77 g ofpropylene glycol monomethyl ether was added to the system, and theresultant mixture was further heated under reflux for 4 hours. Theobtained reaction product, which corresponds to formula (A-2), had aweight average molecular weight Mw of 2,400, as determined by GPC usinga conversion calibration curve obtained from the standard polystyrene.

Synthesis Example 3

12.00 g of a cyclohexane epoxy resin (product name: EHPE3150,manufactured by Daicel Corporation; epoxy functionality: 5.99 eq./kg),4.39 g of 4-hydroxybenzaldehyde, 5.40 of terephthalaldehydic acid, 1.22g of tetrabutylphosphonium bromide, and 34.50 g of propylene glycolmonomethyl ether were placed in a reaction flask and heated under refluxin a nitrogen gas atmosphere for 23 hours. Further, a solution preparedby dissolving 4.75 g of malononitrile in 30.25 g of propylene glycolmonomethyl ether was added to the system, and then the resultant mixturewas heated under reflux for 4 hours. The obtained reaction product,which corresponds to formula (A-3), had a weight average molecularweight Mw of 5,400, as determined by GPC using a conversion calibrationcurve obtained from the standard polystyrene.

Synthesis Example 4

9.00 g of a naphthalene epoxy resin (product name: EPICLON HP-4710,manufactured by DIC Corporation; epoxy functionality: 5.81 eq./kg), 6.39g of 4-hydroxybenzaldehyde, 0.89 g of tetrabutylphosphonium bromide, and24.42 g of propylene glycol monomethyl ether were placed in a reactionflask and heated under reflux in a nitrogen gas atmosphere for 24 hours.Subsequently, a solution prepared by dissolving 3.46 g of malononitrilein 21.63 g of propylene glycol monomethyl ether was added to the system,and the resultant mixture was further heated under reflux for 6 hours.The obtained reaction product, which corresponds to formula (A-4), had aweight average molecular weight Mw of 1,700, as determined by GPC usinga conversion calibration curve obtained from the standard polystyrene.

Synthesis Example 5

13.00 g of a naphthalene epoxy resin (product name: EPICLON HP-4710,manufactured by DIC Corporation; epoxy functionality: 5.81 eq./kg), 4.62g of 4-hydroxybenzaldehyde, 5.67 g of terephthalaldehydic acid, 1.28 gof tetrabutylphosphonium bromide, and 36.86 g of propylene glycolmonomethyl ether were placed in a reaction flask and heated under refluxin a nitrogen gas atmosphere for 23 hours. Subsequently, a solutionprepared by dissolving 4.99 g of malononitrile in 32.13 g of propyleneglycol monomethyl ether was added to the system, and the resultantmixture was further heated under reflux for 4 hours. The obtainedreaction product, which corresponds to formula (A-5), had a weightaverage molecular weight Mw of 1,900, as determined by GPC using aconversion calibration curve obtained from the standard polystyrene.

Synthesis Example 6

10.00 g of a triazine epoxy compound (product name: TEPIC, manufacturedby Nissan Chemical Corporation; epoxy functionality: 10.03 eq./kg),12.25 g of 4-hydroxybenzaldehyde, 0.85 g of tetrabutylphosphoniumbromide, and 53.90 g of propylene glycol monomethyl ether were placed ina reaction flask and heated under reflux in a nitrogen gas atmospherefor 23 hours. Subsequently, a solution prepared by dissolving 6.63 g ofmalononitrile in 15.46 g of propylene glycol monomethyl ether was addedto the system, and the resultant mixture was further heated under refluxfor 5 hours. The obtained reaction product, which corresponds to formula(A-6), had a weight average molecular weight Mw of 800, as determined byGPC using a conversion calibration curve obtained from the standardpolystyrene.

Synthesis Example 7

9.00 g of a triazine epoxy compound (product name: TEPIC, manufacturedby Nissan Chemical Corporation; epoxy functionality: 10.03 eq./kg), 5.51g of 4-hydroxybenzaldehyde, 6.78 g of terephthalaldehydic acid, 1.53 gof tetrabutylphosphonium bromide, and 34.23 g of propylene glycolmonomethyl ether were placed in a reaction flask and heated under refluxin a nitrogen gas atmosphere for 23 hours. Subsequently, a solutionprepared by dissolving 5.96 g of malononitrile in 32.93 g of propyleneglycol monomethyl ether was added to the system, and the resultantmixture was further heated under reflux for 4 hours. The obtainedreaction product, which corresponds to formula (A-7), had a weightaverage molecular weight Mw of 900, as determined by GPC using aconversion calibration curve obtained from the standard polystyrene.

Example 1

To 9.26 g of the solution (having a solid content of 22.7% by weight) ofthe reaction product, which corresponds to formula (A-2) above, wereadded 1.21 g of propylene glycol monomethyl ether and 19.53 g ofpropylene glycol monomethyl ether acetate, to prepare a resistunderlayer film-forming composition in the form of a solution.

Example 2

To 9.40 g of the solution (having a solid content of 22.3% by weight) ofthe reaction product, which corresponds to formula (A-3) above, wereadded 12.23 g of propylene glycol monomethyl ether and 8.37 g ofpropylene glycol monomethyl ether acetate, to prepare a resistunderlayer film-forming composition in the form of a solution.

Example 3

To 7.14 g of the solution (having a solid content of 29.4% by weight) ofthe reaction product, which corresponds to formula (A-4) above, wereadded 14.49 g of propylene glycol monomethyl ether and 8.37 g ofpropylene glycol monomethyl ether acetate, to prepare a resistunderlayer film-forming composition in the form of a solution.

Example 4

To 8.97 g of the solution (having a solid content of 23.4% by weight) ofthe reaction product, which corresponds to formula (A-5) above, wereadded 12.66 g propylene glycol monomethyl ether and 8.37 g of propyleneglycol monomethyl ether acetate, to prepare a resist underlayerfilm-forming composition in the form of a solution.

Example 5

To 8.14 g of the solution (having a solid content of 25.8% by weight) ofthe reaction product, which corresponds to formula (A-6) above, wereadded 13.49 g of propylene glycol monomethyl ether and 8.37 g ofpropylene glycol monomethyl ether acetate, to prepare a resistunderlayer film-forming composition in the form of a solution.

Example 6

To 8.77 g of the solution (having a solid content of 23.9% by weight) ofthe reaction product, which corresponds to formula (A-7) above, wereadded 12.86 g of propylene glycol monomethyl ether and 8.37 g ofpropylene glycol monomethyl ether acetate, to prepare a resistunderlayer film-forming composition in the form of a solution.

Comparative Example 1

To 7.58 g of the solution (having a solid content of 22.9% by weight) ofthe reaction product, which corresponds to formula (A-1) above, wereadded 0.35 g of tetramethoxymethylglycoluril as a crosslinking agent,0.02 g of pyridinium p-toluenesulfonate as a crosslinking catalyst,13.69 g of propylene glycol monomethyl ether, and 8.37 g of propyleneglycol monomethyl ether acetate, to prepare a resist underlayerfilm-forming composition in the form of a solution.

Comparative Example 2

To 7.98 g of the solution (having a solid content of 22.7% by weight) ofthe reaction product, which corresponds to formula (A-2) above, wereadded 0.27 g of tetramethoxymethylglycoluril as a crosslinking agent,0.02 g of pyridinium p-toluenesulfonate as a crosslinking catalyst,13.36 g of propylene glycol monomethyl ether, and 8.37 g of propyleneglycol monomethyl ether acetate, to prepare a resist underlayerfilm-forming composition in the form of a solution.

Comparative Example 3

To 8.12 g of the solution (having a solid content of 22.3% by weight) ofthe reaction product, which corresponds to formula (A-3) above, wereadded 0.27 g of tetramethoxymethylglycoluril as a crosslinking agent,0.02 g of pyridinium p-toluenesulfonate as a crosslinking catalyst,13.22 g of propylene glycol monomethyl ether, and 8.37 g of propyleneglycol monomethyl ether acetate, to prepare a resist underlayerfilm-forming composition in the form of a solution.

[Evaluation of an Optical Coefficient]

Measurement of an optical coefficient was made as follows. Each of theresist underlayer film-forming compositions for lithography prepared inExamples 1 to 6 was applied onto a silicon wafer using a spin coater sothat the resultant film had a thickness of about 50 nm, and heated on ahotplate at 200° C. for 90 seconds. The n value (refractive index) and kvalue (attenuation coefficient) at a wavelength of 193 nm (ArF excimerlaser wavelength), 248 nm (KrF excimer laser wavelength), and 365 nm(i-line wavelength) of the obtained resist underlayer films weredetermined using a spectroscopic ellipsometer (VUV-VASE, manufactured byJ. A. Woolam Co., Inc.). The results are shown in Table 1.

TABLE 1 Example n/k (193 nm) n/k (248 nm) n/k (365 nm) Example 11.56/0.62 1.76/0.09 1.77/0.11 Example 2 1.67/0.19 1.61/0.13 1.74/0.20Example 3 1.61/0.31 1.86/0.46 1.87/0.37 Example 4 1.56/0.33 1.86/0.431.83/0.13 Example 5 1.81/0.41 1.63/0.18 1.92/0.51 Example 6 1.75/0.451.60/0.11 1.84/0.22

In Examples 1 to 6, the resist underlayer film had an appropriate nvalue and k value at 193 nm, 248 nm, and 365 nm. As apparent from theabove results, the film obtained from each of the resist underlayerfilm-forming compositions obtained in Examples 1 to 6 has anantireflection function such that the film can suppress reflection(standing wave) from the substrate, in which the reflection causes anunfavorable resist pattern, in the lithography process using aradiation, such as an ArF excimer laser, a KrF excimer laser, or ani-line. Therefore, the film is useful as a resist underlayer film.

[Test for Release Properties for Film by a Resist Solvent]

Evaluation of the removability of the film by a resist solvent (organicsolvent) was made as follows. Each of the resist underlayer film-formingcompositions prepared in Examples 1 to 6 was applied onto a coppersubstrate having a thickness of 100 nm, and heated at 200° C. for 90seconds, to form a resist underlayer film having a thickness of 170 nm.Then, the copper substrate having the resist underlayer film compositionapplied thereon was immersed in propylene glycol monomethyl ether (PGME)or propylene glycol monomethyl ether acetate (PGMEA), which are generalresist solvents, at room temperature for one minute. The removability ofthe film after the immersion was visually observed. The results areshown in Table 2. In the case where the film was removed, the film wasjudged to have no resistance to the resist solvent (organic solvent),and, in the case where the film was not removed, the film was judged tohave a resistance to the resist solvent.

TABLE 2 Removability of the film by resist solvent Example PGME PGMEAExample 1 No peeling No peeling Example 2 No peeling No peeling Example3 No peeling No peeling Example 4 No peeling No peeling Example 5 Nopeeling No peeling Example 6 No peeling No peeling

As apparent from the above results, the film on the copper substrategiven by each of the resist underlayer film compositions in Examples 1to 6 was not removed (peeled) by PGME and PGMEA, and hence had a highchemical liquid resistance to these organic solvents (resist solvents).That is, the film obtained from each of the resist underlayer filmcompositions in Examples 1 to 6 is free from an unfavorable peelphenomenon due to a resist solvent. Therefore, the film is useful as aresist underlayer film.

[Test for Removability of Film by a Resist Developer]

Evaluation of the removability of film by a resist developer (aqueousalkali solution) was made as follows. Each of the resist underlayerfilm-forming compositions prepared in Examples 1 to 6 was applied onto acopper substrate having a thickness of 100 nm, and heated at 200° C. for90 seconds to form a resist underlayer film having a thickness of 170nm. Then, the copper substrate having the resist underlayer filmcomposition applied thereon was immersed in a 2.38% by weight aqueoussolution of tetramethylammonium hydroxide (TMAH) (product name: NMD-3,manufactured by Tokyo Ohka Kogyo Co., Ltd.), which is an aqueous alkalisolution, at room temperature for one minute. The removability of thefilm after the immersion was visually observed. The results are shown inTable 3. In the case where the film was removed, the film was judged tohave no resistance to the resist developer (aqueous alkali solution),and, in the case where the film was not removed, the film was judged tohave a resistance to the resist developer.

TABLE 3 Removability of the film by resist developer Example (2.38% byweight aqueous TMAH solution Example 1 No peeling Example 2 No peelingExample 3 No peeling Example 4 No peeling Example 5 No peeling Example 6No peeling

As apparent from the above results, the film given by each of the resistunderlayer film compositions in Examples 1 to 6 on the copper substratewas not removed (peeled) by the aqueous TMAH solution, and hence has ahigh chemical liquid resistance to the resist developer (aqueous alkalisolution). That is, the film obtained from each of the resist underlayerfilm compositions in Examples 1 to 6 can suppress an unfavorable peelphenomenon by a resist developer, and therefore is useful as a resistunderlayer film, which requires the development step using an aqueousalkali solution.

[Test for Removability of Film by a Wet Etching Chemical Liquid]

Evaluation of the removability of the film by a wet etching chemicalliquid (basic organic solvent) was made as follows. Each of the resistunderlayer film-forming compositions prepared in Examples 1 to 6 andComparative Examples 1 and 3 was applied onto a copper substrate havinga thickness of 100 nm, and heated at 200° C. for 90 seconds to form aresist underlayer film having a thickness of 170 nm. Then, the coppersubstrate having the resist underlayer film composition applied thereonwas immersed in a 0.5% by weight dimethyl sulfoxide solution oftetramethylammonium hydroxide ((TMAH), which is a basic organic solvent,at 50° C. for 5 minutes. The removability of the film after theimmersion was visually observed. The results are shown in Table 4. Inthe case where the film was removed, the film was judged to have adesirable removability (releasability) by the basic organic solvent,and, in the case where the film was not removed, the film was judged tohave an unsatisfactory removability (releasability) by the basic organicsolvent.

TABLE 4 Removability of film by wet etching chemical liquid (0.5% byweight dimethyl Example sulfoxide solution of TMAH) Example 1 Fullyreleased Example 2 Fully released Example 3 Fully released Example 4Fully released Example 5 Fully released Example 6 Fully releasedComparative No peeling Example 1 Comparative Partially released Example3

As apparent from the above results, each of the resist underlayer filmcompositions in Examples 1 to 6 gave a film on the copper substrate witha more satisfactory removability by the wet etching chemical liquid(basic organic solvent) than did the resist underlayer film compositionsin Comparative Examples 1 and 3. That is, the film obtained from each ofthe resist underlayer film compositions in Examples 1 to 6 can exhibit adesirable removability (releasability) by the wet etching chemicalliquid, and therefore is useful in the semiconductor production process,in which the resist underlayer film is removed using a wet etchingchemical liquid.

[Test for Solubility of Film in a Wet Etching Chemical Liquid]

Evaluation of the solubility of the film in a wet etching chemicalliquid (basic organic solvent) was made as follows. Each of the resistunderlayer film-forming compositions prepared in Examples 1 to 6 andComparative Examples 1 to 3 was applied onto a silicon wafer substrate,and heated at 200° C. for 90 seconds to form a resist underlayer filmhaving a thickness of 170 nm. Then, the formed resist underlayer filmwas peeled off from the substrate, and the obtained film was immersed ina 0.5% by weight dimethyl sulfoxide solution of tetramethylammoniumhydroxide (TMAH), which is a basic organic solvent, at 50° C. for 5minutes. The solubility of the film after the immersion was visuallyobserved. The results are shown in Table 5. In the case where the filmwas dissolved, the film was judged to have a desirable solubility in thewet etching chemical liquid, and, in the case where the film was notdissolved (or was insoluble), the film was judged to have anunsatisfactory solubility in the wet etching chemical liquid.

TABLE 5 Solubility of film in wet etching chemical liquid sulfoxidesolution of TMAH) Example (0.5% by weight dimethyl Example 1 SolubleExample 2 Soluble Example 3 Soluble Example 4 Soluble Example 5 SolubleExample 6 Soluble Comparative Example 1 Insoluble Comparative Example 2Insoluble Comparative Example 3 Insoluble

As apparent from the above results, the resist underlayer filmcompositions in Examples 1 to 6 gave a film with a more satisfactorysolubility in the wet etching chemical liquid (basic organic solvent)than did the resist underlayer film compositions in Comparative Examples1 to 3. That is, the film obtained from each of the resist underlayerfilm compositions in Examples 1 to 6 exhibits a desirable solubility inthe wet etching chemical liquid, and therefore is useful in thesemiconductor production process, in which the resist underlayer film isremoved using a wet etching chemical liquid. Particularly, the filmobtained from each of the resist underlayer film compositions inExamples 1 to 6 can be removed by the wet etching chemical liquid, aswell as it exhibits a satisfactory solubility in the wet etchingchemical liquid, and thus can prevent unfavorable contamination of thechemical liquid, which is caused by ununiform dispersion in the chemicalliquid of removed film (peeled film) as foreign matter (defect).Therefore the film obtained from the resist underlayer film compositionin the Examples is more useful as a resist underlayer film.

INDUSTRIAL APPLICABILITY

In the present invention, there can be provided a resist underlayer filmwhich has a high resistance to a resist solvent, mostly an organicsolvent, and to a resist developer, an aqueous alkali solution, whereasthe film further exhibits removability solely by a wet etching chemicalliquid, preferably solubility soley in a wet etching chemical liquid.

1. A resist underlayer film-forming composition comprising a polymer (P)having a dicyanostyryl group or a compound (C) having a dicyanostyrylgroup, wherein the composition comprises a solvent, wherein thecomposition is free from an alkylated aminoplast crosslinking agentderived from melamine, urea, benzoguanamine, or glycoluril, and whereinthe composition is free from a protonic acid curing catalyst.
 2. Theresist underlayer film-forming composition according to claim 1, whereinpolymer (P) having a dicyanostyryl group or compound (C) having adicyanostyryl group is a reaction product of an active proton compoundand a polymer precursor (PP) containing an epoxy group or a compoundprecursor (PC) containing an epoxy group, respectively.
 3. The resistunderlayer film-forming composition according to claim 1, wherein thedicyanostyryl group is represented by the following formula (1):

wherein X represents an alkyl group, a hydroxy group, an alkoxy group,an alkoxycarbonyl group, a halogen atom, a cyano group, or a nitrogroup; R represents a hydrogen atom, an alkyl group, or an arylenegroup; n represents an integer of 0 to 4; and * indicates a bonding siteto part of polymer (P) or compound (C).
 4. The resist underlayerfilm-forming composition according to claim 1, wherein polymer (P)having a dicyanostyryl group or compound (C) having a dicyanostyrylgroup is represented by the following formula (2):

wherein Q is a group resulting from eliminating m quantity of end atomor atoms from the polymer or compound, wherein m is between 1 and anumber of repeating unit of the polymer when Q is the polymer, and m isan integer of 1 to 4 when Q is the compound, each of m quantity of A isindependently a direct bond or an optionally branched or substitutedalkylene group having 1 to 10 carbon atoms optionally interrupted withan ether linkage, a thioether linkage, or an ester linkage, each of mquantity of B independently represents a direct bond, an ether linkage,a thioether linkage, or an ester linkage, m quantity of R₁ represents ahydrogen atom, a methyl group, an ethyl group, or a propyl group, and isoptionally bonded to Q to form a ring, and each of m quantity of R₂ andR₃ independently represents a hydrogen atom, a methyl group, or an ethylgroup, and each of m quantity of L is independently represented by thefollowing formula (3):

wherein Y represents an ether linkage, a thioether linkage, or an esterlinkage, R represents a hydrogen atom, an alkyl group, or an arylenegroup, n represents an integer of 0 to 4, and each of n quantity of Xindependently represents an alkyl group, a hydroxy group, an alkoxygroup, an alkoxycarbonyl group, a halogen atom, a cyano group, or anitro group.
 5. The resist underlayer film-forming composition accordingto claim 1, wherein polymer (P) having a dicyanostyryl group or compound(C) having a dicyanostyryl group has an aromatic ring or an aliphaticring.
 6. The resist underlayer film-forming composition according toclaim 4, wherein Q in formula (2) has an aromatic ring or an aliphaticring.
 7. The resist underlayer film-forming composition according toclaim 3, wherein R in formula (1) and/or formula (3) is a hydrogen atom.8. The resist underlayer film-forming composition according to claim 4,wherein Y in formula (3) represents an ether linkage or an esterlinkage.
 9. The resist underlayer film-forming composition according toclaim 1 for use on a substrate having copper on the surface.
 10. Anuncured resist underlayer film provided by removing a solvent from anapplied film comprising the resist underlayer film-forming compositionaccording to claim
 1. 11. The uncured resist underlayer film accordingto claim 10, which is formed on a substrate having copper on thesurface.
 12. A method for producing a patterned substrate, comprisingthe steps of: applying the resist underlayer film-forming compositionaccording to claim 1 onto a substrate having copper on the surface andremoving a solvent to form a resist underlayer film; applying a resistonto the resist underlayer film and baking the applied resist to form aresist film; subjecting the semiconductor substrate covered with theresist underlayer film and the resist to exposure; and subjecting theresist film obtained after exposure to development and patterning.
 13. Amethod for producing a semiconductor device, comprising the steps of:forming an uncured resist underlayer film comprising the resistunderlayer film-forming composition according to claim 1 on a substratehaving copper on the surface; forming a resist film on the uncuredresist underlayer film; irradiating the resist film with a light or anelectron beam and subjecting the resultant resist film to development toform a resist pattern; then removing the resist underlayer film exposedin the resist pattern; performing copper plating in the formed resistpattern; and removing the resist pattern and the resist underlayer filmpresent under the resist pattern.
 14. The method according to claim 13,wherein at least one of the steps of removing the resist underlayer filmis conducted by a wet treatment.